Contents

Key Information

What should I do?

If you think you have this condition you should see a doctor within two weeks.

How is it diagnosed?

Your doctor might suspect bacterial vaginosis based on your symptoms and physical examination findings. A vaginal swab can be taken to confirm the diagnosis. You might also have other tests to rule out any sexually transmitted infections.

What is the treatment?

Treatment of bacterial vaginosis is generally straightforward with a course of antibiotics which can be taken orally or as a gel applied to your vagina.

When to worry?

If you think that you have this condition and you are pregnant, then you should see a doctor within 48 hours.

Introduction

Bacterial vaginosis (BV) is a common yet poorly understood condition, in which the balance of bacteria inside the vagina becomes disrupted.

BV doesn't usually cause any vaginal soreness or itching, but often causes unusual vaginal discharge . If you have the condition, your discharge may:

develop a strong fishy smell, particularly after sexual intercourse

become white or grey

become thin and watery

BV isn't serious for the vast majority of women, although it may be a concern if symptoms of BV develop in pregnancy and you have a history of pregnancy-related complications.

Around half of women with bacterial vaginosis have no symptoms.

When to seek medical advice

See your doctor or visit a sexual health or genitourinary medicine (GUM) clinic if you notice any abnormal discharge from your vagina, especially if you're pregnant. It's important to get this checked to rule out other infections and prevent complications.

Your doctor will ask about your symptoms and may examine your vagina. In some cases, a small sample of the vaginal discharge will be taken using a plastic loop or swab, so it can be examined for signs of BV.

Why it happens

The vagina naturally contains a mix of many different bacteria. In cases of BV, the number of certain bacteria increases, affecting the balance of chemicals in the vagina.

What leads to these changes in the levels of bacteria is not clear. BV isn't classified as a sexually transmitted infection (STI) , but you're at a higher risk of developing the condition if you're sexually active.

Women with BV may be able to pass the condition to other women they have sex with, although it's not clear how this happens.

Treatment

BV can usually be successfully treated using a short course of antibiotic tablets or an antibiotic gel you apply inside your vagina.

In most cases, you'll be prescribed antibiotic tablets to take twice a day for five to seven days.

However, it's common for BV to return. More than half of women successfully treated with BV find their symptoms return, usually within three months. Women who have frequent episodes of BV may be referred to a GUM specialist.

Complications

If BV develops in pregnancy, it may increase the risk of pregnancy-related complications, such as premature birth or miscarriage . However, this risk is small and appears more significant for women who have had these complications in a previous pregnancy. BV causes no problems in the vast majority of pregnancies.

As a precaution, you should contact your doctor or GUM clinic if you're pregnant and you begin to have vaginal discharge (although discharge can be a normal part of pregnancy).

Tests for BV are sometimes offered to women during pregnancy or before certain procedures.

Examination

Your doctor or healthcare professional may diagnose BV from a description of your symptoms and by examining your vagina. In particular, they'll look for:

a thin, greyish discharge

an unpleasant smell

In some cases, this may be enough to confirm your diagnosis. However, you may need further tests if you're sexually active and may have a sexually transmitted infection (STI) instead.

Tests

A sample of cells may be taken from the wall of your vagina using a plastic loop or swab. A swab looks a bit like a cotton bud, but is smaller, soft and rounded.

The swab or loop picks up samples of discharge and cells. It only takes a few seconds and isn't usually painful, although it may be slightly uncomfortable for a moment.

The samples are examined to check for signs of BV. In some centres, the result may be available immediately, but it can take up to a week to get the results if the sample is sent to a laboratory.

The level of acidity (pH) of your vagina may also be measured. A swab will be taken from inside your vagina and wiped over a piece of specially treated paper. The paper changes colour depending on the pH level. A pH level higher than 4.5 is an indication that you may have BV.

Bacteria
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease, and some are good for you.

Sexually transmitted infections (STIs)
STIs are diseases passed on through intimate sexual contact, such as vaginal, oral or anal sex.

Vagina The vagina is a tube of muscle that runs from the cervix (the opening of the womb) to the vulva (the external sexual organs).

Treating bacterial vaginosis

Bacterial vaginosis (BV) can be treated successfully with antibiotics.

There's currently no evidence that probiotics, such as those found in some yoghurts, are able to treat or prevent BV.

Antibiotics

Metronidazole is the most common and preferred antibiotic treatment for BV. It's available in three forms. These are:

tablets to be taken twice a day for five to seven days

a single larger-dose tablet you take only once

a gel you apply to your vagina once a day for five days

In most cases, metronidazole tablets taken over five to seven days are recommended, as they're considered to be the most effective treatment. These can be taken if you have symptoms of BV while you're pregnant.

If you're breastfeeding, metronidazole gel is usually recommended, as the tablets can affect your breast milk.

Occasionally, an alternative antibiotic may be recommended instead of metronidazole, such as clindamycin cream applied to the inside of the vagina once a day for seven days. This cream may be prescribed if you've had a reaction to metronidazole in the past, for example.

Whichever course of antibiotics you're prescribed, it's important to finish it, even if you start to feel better. This helps to reduce the risk of symptoms persisting or recurring.

Side effects

Metronidazole can cause nausea, vomiting and a slight metallic taste in your mouth. It's best to take it after eating food. Contact your doctor if you start vomiting when you take the drug. They may recommend trying an alternative form of treatment.

Don't drink alcohol while taking metronidazole and for at least 48 hours after finishing the course of antibiotics. Drinking alcohol while taking this medicine can cause more severe side effects.

Further treatment

For some women, the first course of treatment doesn't treat BV effectively.

If your initial treatment has been unsuccessful, your doctor will need to check you took the medicine correctly. If you did, you may be prescribed one of the different options described above.

If you have an intrauterine device (IUD) that may be contributing to your BV, your doctor may recommend having it removed and using an alternative form of contraception .

Vaginal pH correction treatments

Vaginal pH correction treatments are a relatively new way of treating BV. These usually involve applying a gel to the inside of your vagina that changes the acid balance, making it a less hospitable environment for harmful bacteria. Most vaginal pH correction treatments are available over the counter from pharmacists.

However, it's not clear how effective these treatments are for treating BV. Some studies have suggested they may help, whereas others suggest they're either ineffective or less effective than antibiotics.

Referral to a specialist

If you have repeated episodes of BV in a short space of time, your doctor may refer you to a genitourinary medicine (GUM) specialist for further investigation and treatment.

If you're pregnant, you may be referred to your midwife or obstetrician (a specialist in pregnancies), who can discuss treatment options with you.

Bacteria
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease, and some are good for you.

Inflammation
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.

Sexually transmitted infections (STIs)
STIs are diseases passed on through intimate sexual contact, such as vaginal, oral or anal sex.

Vagina
The vagina is a tube of muscle that runs from the cervix (the opening of the womb) to the vulva (the external sexual organs).

Causes of bacterial vaginosis

Bacterial vaginosis (BV) occurs when there's a change in the natural balance of bacteria in your vagina.

Your vagina should contain bacteria called lactobacilli, which produce lactic acid. This makes the vagina slightly acidic, which prevents other bacteria from growing there.

Women with BV tend to have a temporary shortage of lactobacilli, which means their vagina isn't as acidic as it should be. This allows other types of bacteria to grow.

It's still unclear what causes this change, although your risk is increased if you:

are sexually active, particularly if you have a new sexual partner or multiple sexual partners

use an intrauterine device (IUD) – a contraceptive device that fits inside the womb

smoke

For reasons that are unclear, BV is more common in black women than in other ethnic groups.

rates of BV can vary significantly in different ethnic groups, which can't be explained by sexual activity alone

BV can sometimes occur in women who aren't sexually active

Many experts think sexual activity plays a role in BV, but other factors are probably also responsible for the condition.

Bacteria
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease, and some are good for you.

Sexually transmitted infections (STIs)
STIs are diseases passed on through intimate sexual contact, such as vaginal, oral or anal sex.

Uterus The uterus (or womb) is a hollow, pear-shaped organ in a woman where a baby grows during pregnancy.

Vagina
The vagina is a tube of muscle that runs from the cervix (the opening of the womb) to the vulva (the external sexual organs).

Complications of bacterial vaginosis

For the vast majority of women, bacterial vaginosis (BV) is easily treated and doesn't cause any further problems. However,if the condition isn't treated,there's a small risk you may develop complications.

Pregnancy complications

There's some evidence to suggest untreated BV symptoms during pregnancy can increase your risk of pregnancy-related complications, particularly if you've had these problems in the past.

Pregnancy-related complications that have been associated with BV include:

premature birth – where the baby is born before the 37th week of pregnancy

the amniotic sacbreaking open too early – the amniotic sac is the bag of fluid where an unborn baby develops

chorioamnionitis – an infection of the chorion and amnion membranes (the membranes that make up the amniotic sac) and the amniotic fluid (the fluid that surrounds the foetus)

postpartum endometritis – infection and inflammation of the womb lining after giving birth, particularly after having a caesarean section

See your doctor or visit a sexual health or genitourinary medicine (GUM) clinic as soon as possible if you're pregnant and have symptoms of BV. While your risk of developing these complications is small, treatment may reduce the risk.

If BV hasn't caused symptoms, there's no evidence to suggest it increases the risk of complications in pregnancy. Treatment might not be recommended if BV is detected while you're pregnant but don't have any symptoms.

Sexually transmitted infections

There's evidence that having BV can make you more at risk of catching sexually transmitted infections (STIs), such as chlamydia . This is possibly because the change in bacteria levels inside your vagina reduces your protection against infection.

Pelvic inflammatory disease

Although a link isn't entirely clear, some evidence suggests that BV may increase your risk of developing pelvic inflammatory disease (PID) . PID causes infection and swelling of the upper female genital tract, including the womb, fallopian tubes and ovaries.

Symptoms of PID include:

pain around the pelvis or lower abdomen

discomfort or pain during sex felt deep inside the pelvis

bleeding between periods and after sex

If diagnosed at an early stage, PID can usually be treated successfully with a course of antibiotics. However, an estimated one in five women with the condition become infertile because of severe scarring on the fallopian tubes.

It's important to see your doctor if you experience any symptoms of PID . Delaying treatment or having repeated episodes of PID can increase your risk of infertility.